


Not So Good Boy Armin

by RosaKei



Category: Shingeki no Kyojin | Attack on Titan
Genre: Arumika Week, F/M, Hickeys, I Tried, Lovebites, armin and mikasa are in a relationship, armin tries to top mikasa, arumika, i guess?, idek why i wrote this but here, marking territories
Language: English
Status: Completed
Published: 2019-02-22
Updated: 2019-02-22
Packaged: 2019-11-03 20:36:23
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,932
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17884790
Author URL: https://archiveofourown.org/users/RosaKei/pseuds/RosaKei
Summary: Armin is in control now, and he wants to make sure he marks Mikasa appropriately, as his territory.





	Not So Good Boy Armin

** Disclaimer:I do not own Shingeki no Kyojin / Attack on Titan nor its characters. **

* * *

It was close to midnight, and Armin and Mikasa had just returned from their outing with Eren, back into their shared apartment.

 _5 years._ It was _almost_ 5 years since Armin and Mikasa had gotten together—as a couple. Just a few more minutes and it'd officially be 5 years. If only Eren hadn't invited them out at the last minute to hang out, the two lovebirds would be getting enough sleep for their date the next day. _Oh well._

Armin wasn't sure how he managed to win over Mikasa's beautiful heart, but he was glad that her heart had a special place for him. Mikasa wasn't sure what Armin saw in her that he found so attractive and soothing, but whatever it was she was glad that he was hers and she was his.

"I'm exhausted." Armin yawned. He stretched his arms up tiredly after locking up the door after they had entered, and then flung the keys aside before he flung himself onto the couch. Mikasa eyed him, shaking her head. He could be such a child sometimes… and just the sight of such childishness never ceased to bring back memories from their childhood, the good ones.

"I can tell." Mikasa responded after placing her bag down. A second after, her phone's notification tone echoed the room briefly, causing the raven to take out her phone from her pocket to check.

"Eren?" Armin queried, perking his head up as he drowsily faced his lover, to only witness once again how beautiful she was—and how she brought the beauty out of the outfit she wore. A simple white blouse and pink skirt, with a nostalgic dark red scarf wrapped around her neck suddenly seemed overwhelming for the blonde.

Mikasa gave a nod, her eyes scanning the message she just received, swiftly responding to her brunette friend's text, before setting her phone down on the table as well. "He just wanted to make sure we reached back safely." Mikasa sighed, taking a seat on a chair. "On another note, I never expected to be out for such a long time…"

"That's true, but hey, that time spent together with Eren was fun. I'm glad we three never grew apart." Armin grinned, Mikasa returned a heart-warming smile, a clear sign of her agreement to his statement. They had been friends since they were kids, and now they were in their mid-twenties. It was nice, how they were still all close friends. It was comforting.

It was truly eventful, what the trio did. From movies to ice-skating to an arcade, it was really draining—but all they felt earlier in the day was pure exhilaration. Out of the blue, Armin recalled what Eren had said during their conversation at a café, where they chose to take a break from their activities, when Mikasa had excused herself to the ladies'.

"So, how are things going with Mikasa?" Eren queried curiously as he lifted up his cup of coffee, taking a sip of the hot drink. Armin looked up to him, after having snapped out of the trance he was in when he was stirring his ice lemon tea with the straw he had.

"Everything's going great." Armin beamed, and Eren scoffed in response. And as another response, Armin frowned when he had scoffed, giving a _'what was that for?'_ sort of look that Eren didn't fail to recognize.

"It's just, your so smiley its ridiculously funny. Mikasa really makes you that happy, huh?" Eren mocked in a teasing sort of way. Armin instantly flustered up, although he continued to play it cool as he rolled his eyes. As obvious as it was, his _'play it cool'_ act had failed miserably. "Whatever…so what?" He huffed, before his eyes darted away and back towards his iced lemon tea, deciding to drink it.

"It's just nice to see both of my friends happy, that all." Eren responded. "I still can't believe all this time, we three are still in close contact… and Mikasa still has that red scarf I gave her long back."

Armin's mind during then drifted off to back then, when Mikasa had a major crush on Eren. He had to admit, he was jealous back then. _'Why him, not me?'_ was what he would think. But one thing happened after the other, and now it was Armin and Mikasa dating—as an official couple.

"I knew she had feelings for me back then. And now those feelings are directed at you." He continued to tease, but now it seemed as if the tables had turned from long ago, and now Eren seemed a little envious— at least that's what Armin assumed. Either that or he was just viewing things too in-depth.

Though, it made Armin wonder if Eren had _those_ feelings for Mikasa… and what would've happened if he had acted on them? Well, it was too late now. Both of them knew how committed and loyal Mikasa was—to Armin, in terms of romance of course. And Eren didn't have any plans to ruin whatever chemistry those two shared.

Besides, word on the street was that Eren just recently had a little thing going on with someone now.

"Must be nice, huh?" Eren said, before looking left and right cautiously, as if he were a kid on his way to cross his first road. As the blonde continued to drink his drink, he couldn't help but feel curiosity bubbling in him for the brunette's sudden wariness. And then, what he had blurted out next was unexpected… and perhaps that curiosity was better left unanswered.

"So…" Eren started off, leaning closer to Armin as if he were about to spill some lifelong secrets. Well, not that he had any anyway. "Have you two… you know, done _'it'_?"

Armin instantly choked on his drink. He didn't have to ask what _'it'_ Eren was referring to. Just by Eren's tone, and the smirk he now wore pretty much defined _'it'_ itself.

" _W-Where did that come from?!_ " Armin coughed, his cheeks darkening into shades of red. He was coming close into becoming a tomato. That wasn't an Eren-like thing to ask, or was it? He didn't know. But still…. _Why?_ Why did Eren had to put him in such an embarrassing situation? Were best friends even supposed to talk about this—especially when the other close friend was involved?

Armin wasn't sure what the hell Mikasa was doing in the restroom that took her so long to return from but he knew she wasn't going to come back anytime soon.

" _From that."_ Eren spoke, before pointing towards Armin's neck, where there seemed to be a particular marking left there by a certain someone. Armin flushed even more, he thought his hair and turtleneck shirt was enough to disguise it… but it seemed it want enough to hide it away from Eren's eagle-sharp eyes.

Armin couldn't tell if Eren was asking him this so bluntly because he wanted to tease him or because he was just dense… or both, somehow.

" _S-Shut up!_ I-Isn't this sort of thing w-where you j-just ignore it?" Armin stammered. If he could, he would pull his turtleneck up and hide his tomato face. But even so, Eren probably would know his reaction anyway.

"You're _not_ denying that you didn't do _'it'_ —"

"Where's my privacy, Eren?" Armin cut him off, readjusting his voice.

"I thought us friends shouldn't hide things—"

" _Ereeenn…"_ Armin whined slightly.

"Okay, Okay..." Eren put his hands up a little, as if to surrender… but that wasn't the case. "I'm not asking for details, keep that to yourself." He scoffed before continuing, "But… you know, I've never seen any of those on Mikasa, at least on her neck. Either that or her make-up is good... but she doesn't wear make-up too often so there's that."

"Eren, where are you even going with this?" Armin groaned, "Can't we just talk ab—"

"I'm just wondering if you ever _topped_ her. I mean, it must be tiring for her to always take control or whatever." Eren shrugged, Armin just stared, his cheeks reddening even more. Was that supposed to be advice? In fact, how does Eren even know these sort of things?

_Was Mikasa tired of… that?_

Well, before the conversation could proceed any further, Mikasa had came back. Whether Mikasa's return during then was a fortunate or unfortunate thing was uncertain... considering thanks to Eren's statement, he had developed questions. _Annoyingly bothersome questions._ But he wasn't going to ask them in front of Mikasa. And Eren of course wasn't going to continue that conversation with Mikasa there.

Back in the present, Mikasa stood up from her seat, as she spoke, "Tea?" She asked.

"Huh? Oh… yeah." Armin nodded. But before the raven could make her way towards the kitchen, Armin blurted out… things. "Are you tired… Mikasa?"

"Of course. It's close to midnight—"

"No… not like that." Armin murmured, before sitting up. Mikasa frowned slightly, she wasn't sure what came over Armin, but he looked troubled. _And that troubled her._

"… If you're referring to our relationship, no. I'm not tired of I—"

"It's not that either." Armin sighed, before he stood up and walked towards Mikasa, leaving a few feet away from them. "You know… are you tired from… _taking control?_ " Armin asked nervously. At first, Mikasa was lost as to what he meant. And then, she saw his cheeks tinging an ever-so familiar red. Her cheeks painted itself the same colour upon realization.

"E-Eh? W-Why are you bringing this s-suddenly?" Mikasa stuttered. Regardless of whatever dominant persona she may have, talking about such… things, whether it be in broad daylight or the luminous dark made no difference to the shyness she felt and would display.

"I-If you find it uncomfortable t-to talk about then… never mind." Armin turned his back away. He regretted even bringing it up. Was it normal to bring it up? He wasn't sure. This was a first. _Usually they'd just… go with the flow._ Either way, Armin had no intention of making his lover uncomfortable. But that wasn't the case.

Mikasa got hold of Armin's hand before he could run off and retreat. "W-Wait… it's not that… i-if you're unhappy with something, tell me…" Mikasa spoke. Her tone was nervous, but it dissolved into something more caring, concerned. And a little worry.

"It's not that too! You always make me happy!" Armin exclaimed, before facing back to her. "It's just…" Armin trailed off. Thinking about it now, he came to the realisation that he didn't really leave any marks on Mikasa. Even if he did, they were always faint, and faded away _too_ quickly. And in comparison to the ones Mikasa had left on him, they were practically permanent—not really, but the marks she'd leave on him would just scream out that he was Mikasa's— _her territory and her territory only_.

He wanted to do the same now. He suddenly felt the urge to.

His eyes traced down to her neck, and then it dawned upon him her collarbone was exposed to, thanks to that one unbuttoned button. He bit his lip. He hesitated. He looked up to Mikasa as if to ask for permission.

Mikasa looked back at him. She had noticed all of these things. She then took a step closer to him. She took another step. Her arms wrapped around him. And then, she pressed her lips briefly against his.

For that brief moment, Armin savoured the taste of her sweet lips.

She pulled away. She looked at him directly. She gazed as if she were hypnotized. She parted her lips to speak, "It's okay." She whispered softly. "Express yourself." She permitted.

Without a second to waste, Armin leaned himself forward, closer to Mikasa. Then, his lips met hers again. But the kiss he had with her was deeper, was longer. Mikasa wanted to slide her tongue mid-kiss, but Armin had pulled away before she could.

Mikasa displayed her frustration to it with her piercing look, to which Armin ignored as he began to kiss her cheek, down to her neck. Upon arriving to her neck, the blonde pinned her against the wall ever-so suddenly. It came as a surprise to Mikasa, _but_ she wasn't complaining.

Armin began to kiss her neck. Innocently, he planted simple, gentle kisses all over her neck. Mikasa couldn't tell if this was just his act of being a tease or whatever. But one thing's for sure, she was growing impatient. And even after she told him to express himself, her dominant persona wasn't having any of it. However, just as she was about to let instinct overtake her, Armin began to plant a rather prolonged, deep kiss on her neck. Not just any part of her neck, but her sweet, sensitive spot.

" _Ah!"_ A gasp left the raven's lips. Her arms began to wrap around him tighter. It was clear that the noises and actions on Mikasa's part only motivated Armin more as he practically sucked onto her skin even more. And whenever Mikasa would attempt to overthrow his domination out of pure instinct, the blonde would bite her. Literally. On that sensitive and soft spot of hers.

This was a first. Armin had always been… gentle during moments like these. This was different now. _Mikasa wasn't exactly complaining about that either._

 _"A… Armin…!"_ She grunted out. Armin hadn't marked her this rough. It was new, and she liked it. And it was clearly expressed by the tone of her voice— and the way she'd then tilt her head sideways, as if to give him more skin.

Armin kept going, he'd suck on her skin as if it were the most pleasant thing to taste. He savoured every bit of her, and he couldn't help but bite down on her skin every now and then just for the satisfaction of hearing… certain noises leaving his lover's lips. He never felt like… _this._ _In control_. Normally, he'd just let Mikasa do whatever—he just went with the flow, no complaints, no disobedience. He loved the way she'd satisfy him anyway.

Perhaps this was a turning point in _this_ particular aspect of their relationship. Except for now, it seemed Mikasa was the one who went with the flow… just with some spikes of brief rebellion that Armin managed to put out.

To be fair, Mikasa enjoyed this sensation Armin was giving her. And that enjoyment ten folded when his lips left her neck… to only target her collarbone next. But before that, Armin had taken a glimpse of his artwork. Judging by the sudden smirk his lips wore, Mikasa could've guessed he was satisfied. But other than that smirk, she saw a little happy and somehow innocent smile—as if he were proud of marking his territory— _her_. Mikasa couldn't help but chuckle at that.

Chuckling was probably a bad idea when Armin seemed in his... well, zone. Considering the moment she chuckled, Armin gazed at her in a piercing manner. And he went down to her collarbone, going much ruthless. _"Ah!"_ Mikasa gasped once more, she gripped his shirt tighter. Armin pressed against her chest more, causing both of their cheeks to flush even more so.

"S…Since when did you taste so sweet?" Armin commented in the midst of his marking session. Unfortunately, Mikasa didn't have the chance to answer as Armin began biting down on her collarbone, receiving the raven's noises as a response.

Apparently, it seemed Mikasa's collarbone was another sensitive spot. It was evident since she was squirming more, and more noises left. "A…Armin…" She whimpered.

Something about her calling out his name in such an… exciting way, would flip a switch in him. It was an indescribable sort of feeling. He was learning so much new things about Mikasa thanks to his sudden dominating persona that gradually revealed itself.

Whatever new curiosity he had on her now, he didn't hesitate to experiment.

It didn't seem like this experimentation of his was going to end anytime soon. And it seemed his exhaustion from earlier on had dissipated and shifted into excitement—that much was clear and evident… especially if one were to notice whatever he had _down there._

Well, Mikasa had noticed. It made her blush more. It made her wonder how far this was going to go, with him in charge. At this point, it didn't matter. She just wanted… _more._ She craved more, so did Armin. _But Armin was much more ravenous._

Armin pulled away from her collarbone after he ensured he marked his territory appropriately. His eyes gazed at the love-bites he left on her. He smiled with pride, at how dark they were. He then looked up to his lover who was already gasping for air just a little, he then gazed into her eyes that were practically pleading for more.

His lips met with hers again, but rather than rough, they were gentle. But Mikasa knew better that she shouldn't assume that this gentleness would remain throughout. His eyes then glanced at the clock, he pulled away from her. As the clock had indicated, it had just turned midnight. It was the next day since yesterday. A new today. A special day.

"Happy 5 years, Mikasa Ackerman. I love you." Armin whispered softly.

Mikasa smiled, "Happy 5 years, Armin Arlert. I love you too."

With that, Armin proceeded to lay her down on the couch, where their activities and desires would continue past midnight.

* * *

 

 

 

**Author's Note:**

> Please leave a review, I'd love to hear your thoughts :)  
> also, might change title, idk.


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